[Prior Art Documents]
[Patent Document 1] Japanese Patent Publication (A) No. 09-295908
[Patent Document 2] Japanese Patent Publication (A) No. 11-029410
[Patent Document 3] Japanese Patent Publication (A) No. 2002-226309
[Non-Patent Document 1] Yokoyama et al., Plant Cell Physiol., 41, 110-113, 2000.
Plant growth regulation, in particular the development of technology to promote flower budding in plants, is extremely important in improving the efficiency of supply of farm crops and garden plants. As factors determining flower budding in plants, the day length, low temperatures, plant aging, etc. are known. In plants, the parts sensitive to the day length are the leaf blades. Flower budding occurs at the growth points. It has been learned that some sort of signal is sent from the leaf blade through the stalk and stem to the growth point, whereby the flower budding is started. This signal is generally called a “florigen”. If it were possible to isolate and identify the florigen, it would be possible to artificially regulate the blooming timing of plants, without regard as to the day length. This would have a tremendous effect to many fields where plants are involved.
Therefore, in the past, attempts have been made to artificially adjust the blooming timing by clarifying more the mechanism of flower budding of plants. For example, if administering gibberellin, one growth hormone of a plant, it is learned that flower budding occurs easily in several plants. In addition, it is learned that, in pineapples, blooming occurs by administering one type of synthetic auxin, that is, α-naphthalene acetic acid. This is actually utilized industrially.
Although the situation is as explained above, the effects of these plant hormones are limited. Further advances in blooming techniques, specifically, the isolation and identification of substances directly involved in flower budding and the establishment of a blooming technique using such substances, are desired.
From the above-mentioned situation, the present inventors engaged in intensive studies and, as a result, found that an α-ketol unsaturated fatty acid having the specific structure of the following general formula (2A) acts alone, or in combination with norepinepherine, one kind of catechol amine, to activate the desired flower budding inducing action for a wide variety of plants (see Patent Documents 1 and 2).
Further, thereafter, the inventors engaged in further studies and found that an α-ketol unsaturated fatty acid amide obtained by amide-bonding an amino acid to the carboxyl group of the above-mentioned α-ketol unsaturated fatty acid has a similar activity at a lower concentration (see Patent Document 3).
